The broad objective of the research proposed in this application is to understand the molecular nature of collagen in human gingiva and rat oral tissues. This will involve studies on sub-unit composition, type of collagen monomeric unit, nature of cross-linking, dependence of insolubilization on cross-linking and interaction of collagen with non-collagenous proteins of the extracellular matrix. It is a working hypothesis that oral tissue collagen is unique with regard to one of these characteristics. These studies are intended to extend preliminary investigations which suggests that oral tissues are in a constant state of healing and repair accompanied by higher rates of synthesis and degradation than other connective tissues. The focus of attention will be on the as yet unexplored area dealing with collagen maturation. As an experimental animal, rats will be useful for istopic labeling and aging studies and experiments involving the effect of the lathyrogen, beta-amino propionitrile. Human gingiva at various clinically defined stages of inflammation will be examined in terms of the molecular nature of collagen. This will be performed to investigate if there is a "defect" in the maturation of collagen before or as a consequence of periodontal disease. The methodology involved in this study (column chromatography of intact and cyanogen bromide-degration products, identification of tritium labeled reduced crosslinks, amino acid analysis, etc.) will benefit immeasurably from use of these methods by investigators studying collagen from other tissues. Particular attention will be devoted to analysis of the nature of insoluble collagen from oral tissues.